Imaging based calibration systems, devices, and methods

Patent metadata

Field	Value
Publication number	US-9616251-B2
Application number	US-201414340985-A
Country	US
Kind code	B2
Filing date	Jul 25, 2014
Priority date	Jul 25, 2014
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

Systems, devices, and methods for imaging-based calibration of radiation treatment couch position compensations.

First claim

The invention claimed is:

1. An imaging-based calibration method for a radiation treatment system including a gantry and a couch, the method comprising:
generating gantry-angle dependent isocenter beam deviation information;
generating couch rotation-angle dependent couch position offset information; and
correcting target position by combining the gantry-angle dependent isocenter beam deviation information with the couch rotation-angle dependent couch position offset information.

2. The imaging-based calibration method of claim 1 , wherein the generating of the gantry-angle dependent isocenter beam deviation information includes:
acquiring X-ray images of a calibration device at a plurality of gantry angles;
determining deviations of an isocenter for the plurality of gantry angles from the X-ray images; and
determining a position of a target for each gantry angle based on the corresponding isocenter deviation.

3. The imaging-based calibration method of claim 1 , wherein the generating of the couch rotation-angle dependent couch position offset information includes:
acquiring a plurality of X-ray images of a calibration device positioned on the couch, the couch being rotated over a couch rotation range;
determining positions of the calibration device at a plurality of couch rotation angles from corresponding X-ray images;
translating each determined calibration device position to a couch location;
comparing the acquired couch locations with corresponding reference couch locations; and
calculating a couch position offset value for each couch rotation angle of the plurality of couch rotation angles based on a result of the comparing.

4. The imaging-based calibration method of claim 3 , further comprising determining the reference couch locations for the plurality of couch rotation angles by using a camera-based system or a couch readout system.

5. The imaging-based calibration method of claim 4 , wherein the couch readout system includes a potentiometer, an optical angle, a magnetic angle, or a linear encoder.

6. The imaging-based calibration method of claim 3 , wherein the acquiring of the plurality of X-ray images includes:
positioning the gantry including an X-ray source to a first position and rotating the couch to its maximum rotation angle in a first direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles, then rotating the couch to its maximum rotation angle in a second direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles; and
positioning the gantry at a second position and rotating the couch to its maximum rotation angle in the first direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles, then rotating the couch to its maximum rotation angle in the second direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles.

7. The imaging-based calibration method of claim 6 , further comprising positioning the gantry at a third position and rotating the couch to its maximum rotation angle in the first direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles, then rotating the couch to its maximum rotation angle in the second direction while acquiring X-ray images of the calibration device at a plurality of couch rotation angles.

8. The imaging-based calibration method of claim 7 , wherein the gantry is configured to rotate through 360 degrees, and the first gantry angle position is at 0 degrees, the second gantry angle position is between 30-40 or between 5-60 degrees, and the third gantry angle position is between 320-340 or between 300-355 degrees.

9. The imaging-based calibration method of claim 7 , wherein the gantry is configured to rotate through 360 degrees, and the first gantry angle position is at 180 degrees, the second gantry angle position is between 210-220 or between 185-240 degrees, and the third gantry angle position is between 140-160 or between 120-175 degrees.

10. The imaging-based calibration method of claim 3 , further comprising positioning the calibration device or the couch along a vertical axis at a height, which is at one of the height of the isocenter, above the isocenter, or below the isocenter.

11. The imaging-based calibration method of claim 3 , wherein the first direction is clockwise and the second direction is counterclockwise.

12. The imaging-based calibration method of claim 3 , wherein the couch rotation angles include 1 degree rotation angles.

13. The imaging-based calibration method of claim 3 , wherein the couch rotation range includes the entire rotation range of the couch.

14. The imaging-based calibration method of claim 3 , wherein the X-ray source is an MV X-ray source and the plurality of X-ray images are MV X-ray images, or the X-ray source is a kV X-ray source and the plurality of X-ray images are kV X-ray images.

15. The imaging-based calibration method of claim 1 , wherein the couch offset values for each couch rotation angle include values for displacements of the couch from the reference location in the longitudinal, lateral, vertical and rotational directions.

16. The imaging-based calibration method of claim 15 , wherein the rotational directions include rotations along a pitch axis and a roll axis.

17. The imaging-based calibration method of claim 15 , further comprising storing the couch rotation-angle dependent couch offset values and the gantry-angle dependent isocenter beam deviation information in a tabular database.

18. The imaging-based calibration method of claim 1 , further comprising determining load-dependent couch offset values.

19. The imaging-based calibration method of claim 18 , further comprising correcting target position by combining the gantry-angle dependent isocenter beam deviation information with the couch rotation-angle dependent couch position offset information and the load-dependent couch offset values.

20. The imaging-based calibration method of claim 19 , further comprising determining offsets for collimator jaw or MLC imperfections, wherein the correcting of the target position includes correcting the target position by combining the gantry-angle dependent isocenter beam deviation information with the couch rotation-angle dependent couch position offset information, the load-dependent couch offset values, and the offsets for collimator jaw or MLC imperfections.

21. The imaging-based calibration method of claim 1 , wherein the correcting of the target position includes positioning the target at the isocenter for a particular gantry angle based on the gantry-angle dependent position information and repositioning of the target at the isocenter based on the couch rotation dependent couch offset values.

22. An imaging-based couch displacement determination method, comprising:
positioning a calibration device on a couch;
acquiring a plurality of X-ray images of the calibration device while the couch is rotated over a couch rotation range;
determining positions of the calibration device at a plurality of rotation angles from the plurality of X-ray images and translating each determined position of the calibration device to a couch location information;
comparing the couch location information with a corresponding reference couch location information for each couch rotation angle; and
calculating couch position offset values for each couch rotation angl

Assignees

• Varian Med Sys Inc
• Varian Medical Systems Int Ag

Inventors

• Filiberti Reto W
• Gaudio Stephen

Classifications

• A61N2005/1061

  using an x-ray imaging system having a separate imaging source · CPC title

• A61N5/10

  X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy (A61N5/01 takes precedence) · CPC title

• A61N5/1082

  having multiple beam rotation axes · CPC title

• A61N5/1077

  Beam delivery systems · CPC title

• A61N5/1048

  Monitoring, verifying, controlling systems and methods · CPC title